This invention relates generally to surveying equipment. Surveying equipment and particularly the support structure should be able to withstand all kinds of environmental conditions while retaining its integrity and dimensional accuracy. In many instances, the dimensional accuracy is imperative in order to obtain the correct measurements in a geographic survey. For instance, prism poles and global positioning satellite (GPS) poles should be able to retain a substantially fixed position of extension as they are moved from place to place over uneven terrain and in all kinds of weather.
Prior art prism poles generally include two or more interfitting pole sections, and support a prism or other measurement device at the top used to sight or determine positions with laser, modulated infrared, angular and/or GPS position locators or like surveying systems. The prism reflects light back to the position locator for determining the location of the prism at different locations in a survey. U.S. Pat. No. 5,255,441 explains the operation of a basic prism pole.
One of the disadvantages with poles is that they are problematic when taking measurements of objects at corners, especially corners which have been chamferred (or beveled). With round poles the surveyor must manually position the pole at the point where he believes the corner actually exists. Such an estimate causes inaccuracies in the measurement where the pole is not accurately located.
Another disadvantage with poles is that they add inaccuracies where the surveying shot is taken at an angle of forty five degrees between the two planes forming the corner. Where this occurs the surveyor must compensate for an “odd” angle shot (i.e., one not at exactly forty five degrees).
There is a need in the art for providing improved prism stands.
The following US Patents are incorporated herein by reference: U.S. Pat. No. 5,255,441.
While certain novel features of this invention shown and described below are pointed out in the annexed claims, the invention is not intended to be limited to the details specified, since a person of ordinary skill in the relevant art will understand that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation may be made without departing in anyway from the spirit of the present invention. No feature of the invention is critical or essential unless it is expressly stated as being “critical” or “essential.”